This invention relates to viscous material dispense systems and more particularly to a viscous material dispense system of the type utilizing a nozzle assembly to discharge a material bead in a controlled manner.
When designing a nozzle assembly for discharge of a material bead it is important to be able to precisely control the shape or xe2x80x9cprofilexe2x80x9d of the bead as well as the movement aspect of the bead as it exits the nozzle. It has been proposed to direct a stream of air at the beaded material as it exits the nozzle assembly to attenuate and shape the bead, and, in fact, a multitude of nozzle assembly structures have been designed and utilized including means for directing a stream of air at the exiting bead. However, all of the prior art nozzle assembly air stream designs have either embodied a very complicated and expensive construction, and/or have not been effective to precisely shape the bead and/or have not been effective to impart the desired movement aspect to the bead as it exits the nozzle assembly.
This invention is directed to the provision of an improved viscous material dispense system.
More particularly this invention is directed to the provision of a viscous material dispense system employing a nozzle assembly having means to simply and effectively direct a stream of air against an exiting bead.
The viscous material dispense system of the invention comprises a material source having an outlet; a nozzle assembly including a tubular nozzle member having one end secured to the source outlet, another, free end defining a nozzle tip portion having a conical nozzle surface, and an axially extending main body tubular portion interconnecting the one end and the nozzle tip portion; and a tubular air shroud including a main body portion positioned telescopically over the main body portion of the tubular nozzle member and a tip portion. The main body portion of the tubular air shroud coacts with the main body portion of the tubular nozzle member to define an annular axially extending air passage therebetween and an air inlet communicating with the passage, and the tip portion of the tubular air shroud is positioned proximate the tip portion of the nozzle member and defines a conical nozzle surface coacting with the conical nozzle surface of the nozzle member tip portion to define a conical air passage therebetween communicating with the annular axially extending air passage and opening in surrounding relation to the nozzle tip portion of the nozzle member. With this arrangement, air is introduced at the air inlet and flows as an annular curtain through the axially extending air passage and thereafter flows as a conical curtain through the conical air passage to impinge on a bead of viscous material exiting the nozzle assembly. This arrangement provides a simple and inexpensive means of precisely controlling the profile of the bead.
According to further feature of the invention, the annular axially extending air passage comprises a plurality of circumferentially spaced axially extending flutes, and the conical air passage comprises a plurality of circumferentially spaced radially extending flutes each communicating at one end thereof with a respective axially extending flute. With this arrangement the bead is not only attenuated and shaped by the air stream but the air stream further acts to impart a swirl or spiral movement aspect to the bead. An attenuated, spiraled bead provides a compact spiral pattern which is desirable in many bead application scenarios.
According to a further feature of the invention, the axially extending flutes are defined by axially extending grooves in an outer surface of the main body portion of the nozzle member and the radially extending flutes are defined by radially extending grooves in the conical surface of the tip portion of the nozzle member. This arrangement provides a simple and effective means of providing the desired axial and radial flutes.
According to further feature of the invention, the air shroud is axially shorter than the nozzle member and fits as a cap over the conical tip portion of the nozzle member. This arrangement simplifies the structure of the air shroud and simplifies its positioning over the nozzle member.
According to further feature of the invention, the nozzle assembly further includes a mix tube having one end secured to the source outlet and another free end defining a conical nozzle tip portion, and the tubular nozzle member is positioned telescopically over the mix tube in shrouding relation with its nozzle tip portion proximate the conical nozzle tip portion of the mix tube. This arrangement allows the system to be readily utilized in dispensing a two part material mix.
According to further feature of the invention, the nozzle assembly further includes a tubular conical insert positioned in the mix tube proximate the nozzle tip portion thereof and operative to define the size and configuration of the bead. This arrangement allows the bead size to be readily modified simply by changing the conical insert.
According to further feature of the invention, the nozzle assembly further includes a tubular dispenser tip positioned in the conical tip portion of the nozzle member and defining a conical surface positioned centrally within the conical air passage and forming a radially inwardly extending extension of the conical air passage. This arrangement provides a smooth transition from the air passage defined between the nozzle member and the air shroud to the precise location of the exiting bead.